Init Behat parallel run, e.g.: $ php admin/tool/behat/cli/init.php --parallel=2 Try to use invalid profile: $ php admin/tool/behat/cli/run.php --profile=doesntexist Pass empty 'replace' param: $ php admin/tool/behat/cli/run.php --profile=doesntexist --replace Pass non-matching 'replace' param: $ php admin/tool/behat/cli/run.php --profile=doesntexist --replace=foo Confirm that for each of steps 2-4 you see the message " Invalid profile passed: doesntexist " and do not see a PHP warning about strpos non-string needles Pass matching 'replace' param: $ php admin/tool/behat/cli/run.php --profile=doesntexist --replace=exist Confirm Behat starts run (it will fail later because 'doesnt1' and 'doesnt2' profiles don't exist either): Running 2 parallel behat sites: [behatrun1] vendor/bin/behat --config /var/www/behatdata/behatrun1/behat/behat.yml --profile="doesnt1" [behatrun2] vendor/bin/behat --config /var/www/behatdata/behatrun2/behat/behat.yml --profile="doesnt2"